Patent GB-1438492-A (GB)
Title: Centrifugal separator and liquid aliquoting device
IPC: B04B5/04
Filed: 1972-08-01
Abstract: 1438492 Centrifugal sample dispensing R W A OLIVER 29 Oct 1973 [1 August 1972] 35831/72 Heading G1B [Also in Divisions B1 and B2] A centrifugal separator and liquid dispensing device comprises a first rotatably driven body 2, Fig. 1, a liquid-containing-sample-tube annular support 10 integrally formed, and coaxial with the body 2 and adapted to support capillary sample tubes T, Fig. 3, radially and above an upper surface of the body 2 such that each end E1, E<SP>2</SP> of each tube extends beyond the support 10 above said upper surface, a second body 20 mounted on top of the first body 2 and rotatable therewith, the body 20 being formed with a circular channel 28 adapted to snugly receive the tube support when a relative movement between the bodies 2 and 20 brings them closer together whereby the projecting end portions E<SP>1</SP>, E<SP>2</SP> of the tubes are cut off by the sides 28<SP>1</SP> of the channel co-operating with the sides 10<SP>1</SP> of the support 10, Fig. 1, to leave a central portion C of each tube on the support and outwardly extending radial passages 30 in the body 20 for alignment, after the tubes have been cut off, with the remaining central portions C of the tubes, Fig. 1, whereby liquid can be discharged from each remaining tube portion into a respective passage during rotation of the bodies 2, 20. The bodies 2, 20 are in the form of discs provided with inter-engageable central hub 8 and recess 22. The tubes T are held in radial grooves 14 in the upper surface of the annular support 10 of the disc 2. In operation, the disc 20 is lifted clear of the disc 2 and the tubes T containing samples, e.g. of blood, to be analyzed are laid in the grooves 14. The disc 20 is then lowered in the attitude shown in Fig. 3 and the samples are centrifuged by synchronous rotation of the disc 2 and 20. When the phases have separated, the disc 20 is lowered to the position shown in Fig. 1 whereby the portions E<SP>1</SP>, E<SP>2</SP> of the tubes are cut off and fall into channels 12, 16 in the disc 2 and rotation of the apparatus causes supernatant liquid from the tube portions C to enter the radial passages 30 which, in this position, are sealed at their outer ends by a rim 18 on the disc 2. The disc 20 is then raised to the position shown in Fig. 4 so that the measured volumes of liquid contained in the passages 30 are discharged through. passages 32 in the rim 18. The outer ends of passages 32 may be covered by strips of absorbent paper which receive the measured volumes of liquid for subsequent chromatography. To prevent leakage of liquid from the radial passages 30, each passage may be formed at its outer end with an inverted U shaped portion, Fig. 6 (not shown) through which the liquid contained in the passage will be discharged only by increasing the speed of rotation of the centrifuge. In another embodiment, Fig. 5, a plastics rotor 36 of a high speed analyzer is fitted around the rim of the disc 2 for synchronous rotation therewith. The rotor is formed with circumferentially spaced bores 44 which are closed by transparent annuli 40, 42 e.g. of silica glass, to form optical cells into which the measured quantities of sample liquid are discharged from the passages 32. Each sample may be washed in a respective cell by a syphon technique utilizing an orifice 48. Rotation of the rotor causes each cell to pass in turn through a beam of light directed on to photo-electric means the output of which provides analytical data relevant to the samples. A reference liquid, which may be initially contained in one of the tubes T, may be provided in one of the cells. For synchronous rotation of the discs 2, 20 and the rotor 36 their adjacent faces may be formed with interengaging teeth. In a modification, Figs. 8 and 9 (not shown), a number of measured quantities of liquid samples from the same tube portion C can be simultaneously analyzed in a corresponding number of cells. In a further modification, Fig. 10 (not shown), a measured quantity of reagent, contained in alternate ones of the tubes T, may be mixed with a measured quantity of the liquid sample as both are dispensed to a cell.